Mobile computers that connect directly to the Internet outside of a company’s firewall can introduce risk into the corporate network and thus require a higher level of security to protect against network intrusions. Host intrusion defense systems combine intrusion detection and prevention capabilities, and run on the host itself.This white paper examines a blended approach to host intrusion defense in search optimal security combined with an ideal balance between flexibility, control, and ease of management. Specific examples highlight the benefits and pitfalls of the many different filtering techniques.